The invention relates to a seat back hinge mounting for a forwardly foldable motor vehicle seat, with a first hinge arm and a second hinge arm adapted for relative rotation about a hinge pin, a locking cam, which is disposed on the second hinge arm and is movable between a locking position and a release position, being provided, a first stop flange and a second stop flange being provided on the first hinge arm and the locking cam cooperating with the second stop flange in the locking position and having come free from said second stop flange in the release position.
In prior art, such type adjustment parts are made from one piece, they are mostly made and machined as a blank from a steel sheet. An adjustment part of the type mentioned herein is for example a rear rocker arm of a height adjustment device of an automotive vehicle seat, the reader being referred by way of example to the prior art documents EP 0 445 528 A2 and U.S. Pat. No. 6,264,274 B1. The term adjustment part is understood to refer to an articulated arm of an adjustment device as it is known from the documents DE 103 27 090 A1 and DE 26 04 489 B2 for example. An adjustment part is also an adjustable arm in the adjustment device of a steering column, the reader being referred in this context to the documents DE 197 37 036 B4 and DE 197 37 034 B4 for example. What is characteristic for an adjustment part is that it changes its position relative to a point of reference such as during adjustment, for example of the height of a seat, the incline of a backrest, the angular position of a steering column and so on. An adjustment part in the meaning of the invention often is a four-bar linkage. As a rule, an adjustment part has two functional regions which include bearing regions, articulated regions, toothed regions, guiding regions, clamping regions and fastening regions. Typically, the adjustment part is subjected to considerable load in the event of an accident, more specifically in a vehicle crash event.
It has already been known to manufacture adjustment parts by superposing several thin blanks having the same shape, meaning to build them in a sandwich style. It is also known to manufacture parts from what are referred to as “tailored blanks”, the reader being referred, by way of example, to the Internet site of Thyssen-Krupp with regard to this keyword and to the document EP 1 186 516 A1. Various steel sheet materials are thereby joined together at their narrow side by laser welding. Machining such as blanking, machining a toothed surface feature or an articulated region occurs thereafter. In this way, it is possible to use high-quality material for a region subjected to high load at one end of an adjustment part and a lower cost or lower quality material for the rest.
It is the object of the invention to develop an adjustment apparatus of the type mentioned herein above and the corresponding method in such a manner that individual functional regions of the adjustment part may be made and largely finish machined as pieces from special, particularly suited materials, these pieces being next assembled to form the adjustment part.